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Supplementary Information

Atomic structure of surface defects at mineral-water interfaces probed by

in situ Atomic Force Microscopy

Igor Siretanu, Dirk van den Ende, and Frieder Mugele

Physics of Complex Fluids Group and MESA+ Institute , Faculty of Science and Technology,

University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands

phone: ++ 31 (0)53 489 3089; fax: ++31 (0)53 489 1096; email: i.siretanu@utwente.nl

Supplementary Figure 1. (a) The kaolinite, (b) gibbsite, (c) Na-montmorillonite and (d) illite

crystal structures. Top row-view of a single layer of the clays structure looking down upon the

basal plane. Lower row-side view of the clays structure orthogonal to the basal plane.

Electronic Supplementary Material (ESI) for Nanoscale.This journal is © The Royal Society of Chemistry 2016

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Supplementary Figure 2. High resolution AFM images of defects of various clay particles.

(a) topography image of gibbsite particle (left side, brighter) completely coated with organic

adsorbate on mica substrate (right side, darker) displaying clean crystalline structure. Scale

bar, 2 nm. (b) kaolinite particle with many steps, defects and screw dislocation defects. Scale

bar, 15 nm. (c) atomic resolution phase image of Na-montmorillonite particle close to edge

that display the defect free crystalline structure. Scale bar, 5 nm. (d) topography images of

kaolinite (Kg-2) particle close to edge that display atomic steps, defects and adsorbents. Scale

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bar, 15 nm. (e,e’) Na-montmorillonite atomic resolution topography and phase picture

showing the hexagonal periodic structure with a number of vacancy defects. Scale bars, 2 nm.

(f) high resolution topography picture of kaolinite particle close to the edge that display

monatomic and lattice steps. Scale bars, 15 nm. (g,g’) atomic resolution topography and phase

images of basal plane of Na-montmorillonite displaying a region with well-ordered hexagonal

structure and a region with disordered non-periodic structure. Scale bars, 2 nm.